Implant isolation of silicon two-dimensional electron gases at 4.2 K

Successful lateral electrical isolation of silicon 2-D electron gases (2DEGs) at liquid helium temperature (4.2 K) by ion implantation is demonstrated. The sheet resistance of the implanted regions can be achieved as high as 1 × 10¹³Ωat 4.2 K. Thermal stability up to 550°C makes the technique compatible with most subsequent processing steps to fabricate silicon quantum devices. It has also been confirmed that the 2DEG quality is not degraded by the ion implantation, based on a comparison of Hall mobility of implant-isolated samples with conventional reactive-ion-etching- defined samples.